Master of Science II (Material Science) Examination: Oct/Nov
2016 Semester IV (New CBCS)
SLR No. Day
Date Time Subject Name Paper
No. Seat No.
SLR SH
561
Saturday
19/11/2016
2:30 P.M
to
5:00 P.M
Microelectronics
C
XIV
Instructions: Q.No.1 and 2 are compulsory.
Answer any three questions from Q.No.3 to Q.No.7.
Figures to the right indicates full marks.
Use of non-programmable calculator is allowed.
Total Marks: 70
Q.1
Choose the correct alternative: 14
The most complicated IC Technology today is
NMOS PMOS
CMPS I2L
The buried layer diffusions are made effective the epitaxy
using lithographic techniques.
After Prior
before the heat treatment both a b
In the projected range distribution of impurity follows almost
behavior.
Gaussian erf. c
linear both b c
Heating results in recording of the ion junction into materials.
Heavily doped lightly doped
both a b heating has no effect on position
of the junction
Etch attacks are preferentially faster on oriented Silican.
11>
11 0
Novolac is photoresist.
Negative Positive
both a b neutral
An aspect ratio is
W/L R/L
L/W 1/W.L)
The Ficks 2nd law can be expressed as
Page 1 of 2
In instantaneous source diffusion, surface concentration goes on

increasing decreasing
remains unaffected both a b
10) Phosphorus has a diffusion coefficient of cm2/sec
10 -12 10 -10
10 -14 10
11) In VLSI CMOS circuits, high substrate doping is to prevent

latch minimize the junction
capacitance.
minimize the junction
temperature
minimize the power loss
12) Isopoly photo resist 747, MR) is photo resist.
positive negative
both a b none
13) Emitters of transistors are fabricated by
constant source diffusion instantaneous source diffusion
interstitial diffusion self diffusion
14) of CMOS is one of its important attributes for high density
applications.
low power consumption high power consumption
fabrication process
sequence
both a b
Q.2 Attempt the following.
Discuss: diffusion vs epitaxy 04
Printed Grid Array 05
Flat package 05
Q.3 Discuss. What are substitutional and interstitial diffusions? 10
Molecular Beam Epitaxy for the growth of high quality films. Discuss. 04
Q.4 Discuss in brief an ion implantation process for implantation of ions in an
epilayer.
10
Mention the salient features of an ion impliantation. 04
Q.5 State and explain Fick's 2nd law of diffusion. 10
What is constant source diffusion? 04
Q.6 Discuss evaluation of an epitaxial layer referred to: 10
measurement of resistivity
ii) measurement of layer thickness
iii) doping profile
Write a note on thermal oxidation. 04
Q.7 Mention characteristics of a good photo resist with a suitable example.
Explain negative and positive photoresists.
09
Write a note on n MOS device. 05